A newly revealed Al Qaeda video calls on followers to launch cyberattacks on Western targets, a message called "alarming" by U.S. lawmakers in light of the increase in such attacks last year.

Sens. Susan Collins and Joe Lieberman, chairman of the Senate Homeland Security Committee, say they first learned of the Al Qaeda video a week ago in a meeting with Homeland Security Secretary Janet Napolitano.

“This tape is really alarming,” Collins, R-Maine, told Fox News. “It's essentially instructing anybody who's sympathetic with Al Qaeda's ideology to engage in cyberattacks, and the tape is telling them how easy it is to do so.”

The six-minute video instructs Al Qaeda followers that the U.S. is vulnerable to cyberattacks in the same way airline security was vulnerable in 2001 before the terrorist attacks of Sept. 11. The video calls on Muslims "with expertise in this domain to target the websites and information systems of big companies and government agencies."

Lieberman, I-Conn., said it's hardly surprising that Al Qaeda would turn to such attacks.

More On This...

“Al Qaeda and Al Qaeda in the Arabian Peninsula are focused on cyber warfare because it can be carried out, if you have somebody smart enough, at very little expense,” Lieberman said.

The senators said the Homeland Security Department responded to 100,000 cyber incidents in 2011, and there was a five-fold increase in the number of attacks aimed at industrial control systems. They are the central nervous system of critical infrastructure, including power plants and dams.

“There has been a huge increase in the number of cyberattacks against our country in the last two years,” Collins said. “It would be naive for us to think that Al Qaeda is not responsible for at least some of those attacks.”

Without getting into classified information, Lieberman confirmed that there has been a spike in cyber intrusions -- believed to originate with Iran.

“There is real evidence that the Al Qaeda groups want to pursue and are beginning to pursue the capacity to launch a cyberattack against America,” he emphasized. “I mean, that is the real and present danger and that Iran will share that cyberattack capacity with terrorist groups.”

Fox News has learned this so-called electronic jihad was part of a two-hour Al Qaeda online video that was the basis for the FBI and Homeland Security intelligence bulletin last summer about possible lone wolf attacks. Asked why it took so long to flag the specific threat to the Senate committee, neither federal agency gave an immediate response.

The Senate is scheduled to take up its version of legislation tackling cyber security next month.

Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security. Herridge joined FNC in 1996 as a London-based correspondent.